Death Roll (Combat)Source Inner Sea Races pg. 204
Like an alligator, you twist and wrench your foe, forcing him to the ground.
Prerequisites: Bite attack, reptilian subtype.
Benefit: When grappling a foe of your size or smaller, you can attempt to perform a death roll. Upon a successful grapple combat maneuver check to deal damage with your bite attack, you can immediately attempt a second grapple combat maneuver check as a free action. If successful, you knock the target prone. Upon knocking the target prone, you must either release the grapple or fall prone and maintain the grapple. This doesn’t count as a combat maneuver check to maintain the grapple, and doesn’t add any other effects (such as constrict) beyond knocking the target prone.